I will start out by saying that I had low testosterone before I started taking this product. I noticed after a couple of weeks that my mood was much better, all day, every day. I was thrilled with just that. My libido has improved and my muscle tone has also improved. My T has increased to a mid-normal range. I am taking two tablets daily, one in the morning and one in the evening with dinner. When the bottle ran out, after 45 days, I took a two week break. During this time my mood was bad, I felt depressed, energy was low, couldn't focus as well. I went back on the product, 2 tabs daily, and everything started to improve once again within a few days. The only reason I gave it a 4 and not a 5, is due to a slight nauseous feeling. This went away after the first week. This is my story, you may experience something different. I believe Tribulus works best if you have low T. You may not feel any effect if your T is already normal or high.